GM Service Manual Online
For 1990-2009 cars only

Class 2 Serial Data Link

The Class  2 serial data link allows these modules to communicate data with each other:

    • Body Control Module (BCM)
    • Electronic Brake Traction Control Module (EBTCM)
    • Heater-AC control (if equipped with RPO CJ2)
    • Inflatable Restraint Sensing and Diagnostic Module (SDM)
    • Instrument cluster
    • Powertrain Control Module (PCM).

In addition, the Class 2 serial data link allows a scan tool to communicate with these modules for diagnostic and testing purposes. The Class 2 serial data link is located at the DLC connector terminal 2, which consists of circuits 1036, 1037, 1038, 1049, 1122, 1128 and 1132.

Entertainment and Comfort (E&C) Serial Data Link

The Entertainment and Comfort (E&C) serial data link allows a scan tool to communicate with the radio and Remote CD player (if equipped with RPO U1S) for diagnostic and testing purposes. In addition, the E&C serial data link allows the radio and the Remote CD player (if equipped with RPO U1S) to communicate data with each other. The E&C serial data link is located at the DLC connector terminal 14, circuit 835.